This disclosure generally relates to improvements in portable apparatus for use primarily by firefighters.
Chemical agents are frequently added to water by firefighters to enhance the firefighting properties of plain water. These additives include but are not limited to compounds for better extinguishment and wetting ability, and for increasing the volume of the water which is useful in blanketing areas with foam. In recent years many types of additives have been found useful for fire departments.
Some agents or additives when proportioned into water can be made to form foam when aspirated with air. These additives when in their liquid state are referred to as foam concentrates. The foam that is formed is sometimes designed to form a blanket that covers burning hydrocarbon fires, whereby the blanket floats, and spreads out to seal off the formation of flammable vapors. Liquid fuels are referred to as CLASS B. Other foams are intended to form a thick blanket over hydrocarbons or chemicals in order to inhibit the formation of vapors that could ignite, or are harmful. Vapor mitigation of hazardous materials is referred to as HAZMAT.
Recent advances have been made in new types of water additives that are intended to be applied to solid organic fuels such as wood, brush, pine needles, grass, grain and the like. These solid carbon based fuels are referred to as CLASS A. The water additives for CLASS A fuels greatly enhances the penetrating and wetting ability of the water. When wetting ability or reach is the dominant factor, the solution (water plus additive) is usually applied in a straight jet. Other water additives not only act as wetting agents, but are designed to be mixed with water, and are aspirated with air to form foam. Sometimes it is desirable to apply the solution in a wet sloppy foam for soaking down into a deep fuel load, such as several inches (or 200 mm) of pine tree needles. Other times the foam is applied in thick blankets for its insulating ability in protecting against the advancement of fire.
It is apparent that the methods and tactics for applying these different types of chemicals are quite varied; however the usefulness and effectiveness of adding chemical concentrates to plain water is well known to the modern firefighting services.
The addition of chemical foam concentrates to water by fire department personnel has been done in a variety of ways, but can be generally classified into two methods. One method is to add the concentrate to the water at or near the fire truck. The second method is to add the concentrate approximately at the point of usage, that being the discharge end of the fire hose.
While portable foam reservoirs containing water and foam concentrate in either liquid of pellet form have been used for several years, such as the "Light Water" brand solid AFFF sold by 3M, and the type sold by Scott Plastics LTD company of Victoria BC Canada, the reservoirs have substantially limited usefulness as a portable unit because the majority of their weight is in water. Consequently, their extinguishing ability is severely limited, and they will not achieve the effectiveness as a portable system as the present invention if constructed of an equal weight.
The present invention relates to point of usage type of proportioning systems connected to a pressurized source of water by a hose. Point of usage proportioning systems can be further divided into those systems that have the concentrate pumped through a separate hose to the point of usage, and those systems generally referred to as portable. The present invention is classified as portable.
Portable proportioning systems are intended to be stored in a ready to use condition so that they can be quickly deployed by a single person. Adding concentrate at the point of usage with portable systems has in the past been generally limited to smaller applications of foam because of the logistical limitations of having to carry the concentrate to and around with the end of the hose. This method however can be advantageous over truck dispensed concentrate systems because the person applying the foam can control the dispensing of the foam concentrate. In truck mounted systems, this control is given to the pump operator who cannot see nor respond to the changing fire area situation as quickly as the person at the end of the hose. This method is advantageous over point of usage methods with pumped concentrate supply for the same reason, and in addition portable systems have increased mobility.
The benefit of releasing a chemical into the environment must be weighed against the potential for damage on the environment. It is becoming increasingly evident that spillage and wastage should be kept to a minimum. Small portable systems can quickly and easily be brought to the scene and used with high accuracy so that environmental impact is minimized.
Portable point of usage systems including flexible foam storage bags designed to be worn by the firefighter have been used, such as a system depicted in U.S. Pat. No. 5,137,094, and those appearing in a catalog of Scott Plastics Limited, Victoria BC Canada. While they may be comfortable to wear for extended periods of time, they must be strapped on, thereby decreasing their speed of deployment. Only one type of discharge device is connectable to the discharge end of the hose at a time, and there is no provision for self contained storage of a variety of discharge devices. Thus these systems have a limitation in that, when a different discharge device is needed, it will probably not be immediately available.
In Europe, a portable point of usage proportioning system has been manufactured by the Delta Fire company in the UK. This system is usually stored connected to a fire hose, and can be instantly picked up and carried to the scene. It is equipped with rapid connectors so that either low expansion or medium expansion foam aspirating nozzles can be connected to a discharge hose. However, this system has no provision for storage of these multiple attachments or discharge devices in a unitized package. The attachments are therefore likely to be misplaced or lost, or become unavailable to the operator at the time when they are needed when the system is in use at the end of the hose.
Wheeled carts containing foam reservoirs, a discharge device, and an eductor are not truly portable because they are too heavy to be carried. For example a cart of typical size sold by Angus Fire Armour weighs over 400 lbs (183 KG) when filled with foam additive. A cart lacks speed of deployment and mobility at an emergency scene such as a vehicle crash, moving in rough terrain, or in structures where stairs are present. The hose into the reservoir is of a considerable length, making detection of the remaining foam supply by the nozzle operator difficult or impossible. These systems are intended to be operated by one person at the foam tank, and one person at the nozzle. Further, these systems are equipped with only one type of nozzle, and thus are limited in the style of discharge they can produce.
It is a general object of this invention to provide an improved portable system which avoids the foregoing disadvantages of the prior art.